1. Technical Field
The present invention relates to a light-adjusting unit and a projector.
2. Related Art
In the related art, a projector configured to modulate a light flux emitted from a light source unit by a light-modulating unit according to an image signal and project the modulated light flux on a screen or the like as image light is known. Examples of such a projector include those having a light-adjusting unit configured to adjust the light amount of the light flux to be caused to enter the light-modulating unit corresponding to the brightness of an image to be projected. The projectors having such a light-adjusting unit provide high dynamic contrast.
A light-adjusting unit disclosed in JP-A-2010-175679 includes a dimming unit configured to dim a light flux emitted from a light source, a second gear and a third gear having the dimming unit mounted thereon and configured to rotate for changing the position of the diming unit, a base portion having a supporting shaft configured to rotatably support the second gear and the third gear and configured to sandwich the second gear and the third gear respectively with an optical component housing in the direction substantially orthogonal to an axial center of the supporting shaft. In this configuration, the supporting shaft is allowed to be projected from a rotating portion, the rotating portion is prevented from coming apart from the supporting shaft without arranging a guard ring or the like, and a stable rotation is achieved by changing the position of the dimming unit adequately.
In the light-adjusting unit disclosed in JP-A-2010-175679, the second gear and the third gear rotate by being supported by a substantially column-shaped supporting shaft fixed to the base portion. However, the second gear and the third gear supported by the supporting shaft in this manner have a problem of being subject to inclination with respect to the supporting shaft after a long time use, and hence being liable to rattle during the rotation thereof. Also, the light-adjusting unit has a problem that the position of the dimming unit (light-shielding plate) is shifted by the rattling of the rotation of the gears and hence the light shielding for shielding the light to a predetermined passing light amount is not achieved, so that light-adjusting control cannot be performed with high degree of accuracy. Accordingly, the projector provided with the light-adjusting unit has a problem that high dynamic contrast which is maintained for a long time is not obtained.
Therefore, a light-adjusting unit capable of preventing rotation from rattling even after the long time of use and a projector having such a light-adjusting unit have been demanded.